Card perforator with spot detector



Feb. 7, 1939. c EHRET CARD FERFORATOR WITH SPOT DETECTOR 4 Sheets-Sheet 1 Filed Sept. 11, 1936 E QW INVEN'OR ATTORNEY Feb. 7, 1939. c. EHRET 2,145,291

I CARD PERFOR'QTOR WITH SPOT DETECTOR Filed Sept. 11, 1935 4 Sheets-Sheet 2 INVENTOR QM alf' 7k 720. W z

ATTORNEY Patented Feb. 7, 1939 UNITED STATES- PATENT OFFICE CARD PERFORATOR WITH SPOT DETECTOR Clement Ehret, White Plains, N. Y., assignmto International Business New York, N. Y.,

22 Claims.

machines, the cards must be free of any defects or flaws which might interfere with proper operation of the controlled machines. Particularly is this true where the control of the machines is effected electrically through electrical analyzing means which analyze or search the. records for holes and in accordance with the'analysis cause selective operation of the accounting machines. A record sheet or card for the electrically controlled machines must be free of conductive spots or any holes no matter how small through which a false analysis may be made by the card searching elements.

In order to prevent record cards defective by reason of conductive spots or other flaws to enter into the accounting system, it is desirable to eliminate the defective cards in the first stage of their preparation as control media. This first stage of preparation is to punch holes in the cards according to a selected code to represent desired data. The punching oi! holes in the cards is done by a perforating machine which has a keyboard for controlling it and usually an additional pattern card section for selecting the holes to be punched according to a prepared pattern punched in a master or pattern card. e i

, The object of the invention may be stated as the elimination of defective cards during the punching operation or during their passage through the punching machine.

Further, the object is to detect flaws in the blank record card as it is fed to the punching station proper and in case of a defect being detected to withhold the punching of the card and to immediately pass the card through and past the punching station without accompanying opera-' tion of the punching means.

It is a further object to so treat the defective cards as to mark their defectiveness.

The latter object, more specifically, is to sever the defective cards lengthwise as they are fed out of the punching station to obviate any possibility of their being run through the punching machine again.

The above objects are accomplished by combining with the punching machine a device'for detecting and destroying defective cards as they are run through the punching machine.

Other objects will be apparent from the further -tion of the machine.

Machines Corporation,

a corporation oi New York Application September 1'1, 1938, Serial No. 101,255

parts of the specification and in which.

Fig. 1 is a side view of the machine. a Fig. 2 is a detail section taken through the spot detecting brushes. Fig. 3 is a detail of the escapement feed release mechanism.

Fig. 4 is a plan view of the machine. Fig. 5 is a detail central section through a porfrom the drawings,

. Fig. 6 is a detail plan view of the rear part of the machine with a surface part broken away to show the interior, and

Fig. 7 is a circuit diagram. i The punching machine is'oi the type shown in Patent No. 1,772,186. Only such details of the punching machine will be described herein as are required for an understanding of the present invention. New parts may be referred to as special.

The machine has keys Ill depressible to select the punches for operation. Upon depression of a key l0, it acts through a connecting lever H to. advance an interposer l2. The advance of the interposer brings the upper edge beneath a hammer tip I3 carried by a pressure plate It. Before its advance, the interposer has a notched forward end below the hammer tip. Thus, upon depression of the hammer tip, it will not strike the interposers left in initial position but will strike the upper edge of the advanced interposer and force the latter downwardly to depress the punch IS on which the interposer rests. The depressed punch I5 coacts with a die hole in die plate It to punch a. hole in the work card T. The card..has parallel columns. of perforation-receiving positions (see Fig. 4) and the punches are arranged in a single line to selectively punch one card column at a time.

Keys Ill may be manually or automatically depressed to selectthe punches for operation. For automatic operation, they are connected to armature levers II, the armature plates iii of which are in cooperation with selecting magnets 20. The magnets are selectively energized under control of a pattern card P (see Fig. 4) the perforations of which are sensed by an analyzer com-- prising a set of ball contacts 2| (see Fig. '7) and a cooperating contact roller 22. When a hole in a column of the pattern card comes beneath a ball 2|, the latter protrudes through the hole into engagement with the contact roll and closes a duplicating circuit through a magnet which operates the proper keyi'or selecting the punch to duplicate the sensedpattern card hole in the work card T.

A typical duplicating circuit may be traced as follows (see Fig. 'I)

Duplicating circuit.From supply line 24, through normally closed contacts 25, 26-, and 21, contact roll 22, the ball 2| engaged therewith through a perforation in the pattern card, the magnet 20 connected to this ball, common line 26, normally closed contact 29, special, normally closed relay contacts 33a of a special relay 30 and to the opposite supply line 32.

Energization of the magnet 2|] acts through elements l3 and I! to depress the associated key I! for selecting the punch for operation. As explained before, the selection is effected by advancing an interposer to effective position below hammer tip ll of pressure plate I4. The advance of any of the punch interposers causes contacts 33 (see Fig. 7) to close. The mechanical means for closing these contacts are not illustrated here, as these means are fully disclosed in the aforementioned Patent No. 1,772,186.

Upon closure of contacts 33, a punch operating circuit is closed as follows (see Fig. 7)

Punch operating circuit.From line 32, through contacts 33, punch operating magnet 34, and to line 24.

Punch operating magnet 34, when energized, operates linkage 35 (see Fig. 5) to depress plate I4 causing hammer tip [3 to depress the advanced interposer i2 and the punch I5 underlying it, thus effecting punching of a hole in the card T.

Upon depression of the advanced interposer, the latter also rocks a ball 36 (Fig. 5) to rock a member 31 (Fig. 3) counterclockwise, thereby raising escapement pawl 36 from escapement rack 39 and lowering escapement dog 40 into engagement with the rack. The escapement rack is thereby held against advance. After the punching operation, upon return upwardly of the depressed interposer, ball 36 and member 31 return clockwise, causing dog 46 to release rack 39 and pawl 33 to again engage the rack. In the interim between release of the rack by pawl 36 and the return to engagement with the rack of the pawl, the rack is advanced one tooth distance equivalent to a column advance of the card.

For full details of the escapement mechanism, recourse may be had to Patent No. 1,426,223 or Patent No. 1,772,186 (Fig. 17).

Referring to Fig. 4, the escapement rack carries oppositely and laterally extending parts 42 and 43 respectively in rear of the pattern card P and work card T and also carries oppositely extending parts 44 and 45 respectively engaging the forward edges of the pattern and work cards. As may be seen from Fig. 5, part 43 pivotally carries a pusher element 46 for engaging the rear edge of the work card. Thus, upon advance of escapement rack 33, the pattern and work cards are constrained to move with the rack and to the same extent. Parts. 42, 43, 44, 45, and 46 may be referred to as the card carriage.

The blank cards T to be punched are stacked in a supply magazine 48 at the rear of the machine. The bottom card of the stack is fed to i the card carriage by a picker 50 (see Figs. 2, 4,

and 6). Picker 50 is mounted on a bracket 6i which carries a finger handle 52. Bracket 5| is also rigidly connected to a slidable rod 53. To feed a card from magazine 46 to the card carriage, the operator grasps handle 52 and moves the parts connected thereto to the left (Fig. 1), through their forward stroke. Picker 66 which is engaged with the rear edge of the bottom card T thereupon advances the bottom card until the rear edge of the card is in front of pusher 46 of the card carriage. The card is thus delivered to the card carriage.

During the forward stroke of the picker mechanism, the escapement mechanism and connected card carriage are returned to the right by connections to rod 53. The picker mechanism at the end of its forward stroke is automatically returned to its initial position while the card carriage remains in the rear position, in which the card delivered thereto has its first column in punching position. Column by column advance of the card is then effected incidentally t'o successive punching operations while the picker mechanism remains in rear position.

The picker mechanism and the return operation under its control of the escapement and carriage are fully disclosed in Patent No. 1,772,186 and need not be further explained herein.

When the picker mechanism is in rear position, the rear horizontal edge of bracket 51 is abutting a lug 55,formed on a horizontally rockable lever 66 (see Fig. 6) and is holding the lever to the right. In this position of the lever, its insulating piece 5'! is forcing a spring blade 58 towards a spring blade 59. Blades 68 and 59 carry contacts 25 previously referred to in tracing the duplicating circuit. When blade 68 is forced towards blade 56 by piece 51, contacts25 are closed. At the same time, a special insulating rod 61 secured to blade 59 is engaging a special spring blade 62 and holding its contact point 63 away from the companion point 63 on a special blade 64. Thus, initially, special contacts 63 are open and contacts 25 closed. At the beginning of the forward stroke of the picker mechanism, bracket 5i releases lug 65 of lever 56 and spring blade 58 moves away from blade 59, permitting contacts 25 to open and special contacts 63 to close. The purpose of contacts 63 will be brought out later.

In addition to the character keys 13 of the keyboard, the latter is provided with the usual release key R (see Fig. 4). Referring to Fig. 3, depression of release key R acts through a bell crank 66 to move a bar 61 to the. right, causing the bar to ride up on its support 63. Bar 61 underlies a skip lifter 66 so that rise of bar 61 elevates the skip lifter. The latter, in turn, raises escapement pawl 36, thereby freeing escapement rack 39 for uninterrupted continuous advance to the end of its forward stroke. As rack 39 moves to the end of its forward stroke, the card carriage moves the work card T and pattern card P to the positions shown in Fig. 4. The work card T may then be removed by the operator. At the end of the forward stroke of the escapement rack, a member 68 carried thereby strikes the forward, downwardly bent end of release bar 61 and returns it to initial position.

Departing from previous construction, release key R is connected to a special armature lever 10 provided with an armature 30' (see Fig. 5) for coacting with previously mentioned special release magnet 30 (see Figs. 4 and 7). Energization of magnet 30 automatically operates key R to effect automatic release operation of the escapement and card carriage. At the same time, energize.- tion of magnet 30 in depressing lever Ill, causes the latter to open contacts 360 (see Figs. 5 and '1) of the duplicating circuit, previously traced. Thus, operation of the release key mechanism prevents making of any duplicating circuits under control of the pattern card during ejection of the work card by release movement of the escapement mechanism.

i 'Thus-far, with the exception of those special parts to which attention has been called, the usual card punching mechanism has been described. The spot detecting means and the means for rendaring defective cards unfit for further use.will beexplained now. v

'The spot detecting brushes'l5 (Figs. 2, 5, and 7) are located directly behind the card carriage part 43 (see Fig. 5) and in front of the mouth of the supply magazine 48. The brushes are arranged in a line across the width of the card carriage so as'to sense the entire width of the card. In the event a conductive spot of the card comes beneath brushes 15,- the latter: are conductively connected through the card spot-to a contact plate 18 providedat the top of a lever 11 normally urged by a spring 18 in a clockwise direction (Fig. 2').

Detecting brushes 15 are mounted on a shaft 88 journal'ed in the frame for rotational movement. One end of shaft 88 (see Fig. 1) carries a crank arm .8I connected by a link 82 to an armature lever 83 acted on by a spring 84 and controlled by a magnet 85. Normally, spring 84 holds shaft 88 in counterclockwise position so that brushes 15 are lowered and in operative spot detecting position, indicated in Fig. 2. When magnet 85 is energized, it causes shaft 88 to rock clockwise (Fig. 1) thereby raising brushes 15 into inoperative card sensing position, indicated in Fig. 5.

Initially, magnet 85 is deenergized and brushes 15 are in lower, operative position. Now, as picker 58 feeds the bottom card T out of magazine 48, the card rides between brushes 15 and plate 18. Before the rear edge of the card is moved into position in front of card carriage pusher 48, the entire lengthof the card has passed brushes 15. Thus, should a conductive spot occur at any part of the card, it will be sensed by brushes 15 to form the following circuit (Fig. 7)

Spot detecting circuit-From line 32, through a special switch 88, a feeler 81, the contact bar 88, brushes 15, contact plate 18, relay magnet 98, and through contacts 21 to line 24.

Before the card reaches brushes 15 and after leaving the brushes, the latter engage the bare contact plate 18. To avoid formation of a spot detecting circuit during these periods, the latter circuit is made through feeler 81 and contact bar 88. Contact bar 88 is fixed to the frame and has insulating portions at the front and rear ends. Feeler 81 is carried by bracket 5I of the picker mechanism and moves along bar 88 in correspondence with the movement of the picker mechanism and the card fed out of magazine 48 by picker 58. Feeler 81 wipes the conductive part of bar 81 only while the card is beneath brushes 15, therebypreventing making of the spot detecting circuit at other. times.

When relay 98 is. energized by the spot detecting circuit, it closes contacts 98a and 98b. Closing of contacts 98a forms a holding circuit through relay 98 which by-passes elements 15, 18, 81, and 88, so that after the defective spot passes the detecting brushes, relay 98 remains energized until contacts 21 open. Contacts 21 are known as the last column contacts and do not open until the last card column has passed the punches I5.

, Thus, after a conductive spot" has been detected, magnet 98 remains energized until the card has been ejected from the punching station. During this interval relay contacts 98b also remain closed forming the following circuit? V From line 24, throughlast column contacts, 21, signal 9|, solenoid 92 (which controls the card marring or cutting means to be described later), release magnet 88, contacts 981, and through switch 88, to line 22.

' The above circuit energizes release magnet 38, which as explained before operates mechanism for releasing the escapement bar 89 and the card carriage for continuous movement to the end of its forward stroke. However, while the picker mechanism is feeding the card to the card carriage, the escapement mechanism is concomitantly and positively being moved rearwardly. Thus, the release mechanism has no effect until the picker has moved the card to the card carriage at which time the return stroke of the carriage has been completed. With the card T delivered to the card carriage and the release magnet still energized, the escapement mechanism is released for immediate movement through its forward stroke, thus ejecting the card from the punching means. Further, energization of release magnet 38 has opened contacts 30a so that punching circuits cannot form under control of the pattern card during the aforesaid ejection of card T. h

During ejection of the card, solenoid 92 is energized by the last described circuit. Referring to Figs. 1, 4, and 5, solenoid 92 is located. in front of the punching station. Plunger 93 of the solenoid is connected by a linkage 94 to'a lever 95 which rotatably carries a slitting disk 98. A spring 91 connected to lever 95 normally holds the slitter disk 98 elevated and clear of a operating slitter disk 98; Thus, normally, the card moves past the slitting disks without engaging the latter. When solenoid 92 is energized, it causes disk 98 to move down into cutting cooperation with disk 98. Now, as the card moves past the disks 98 and 98, .the latter slit the card,

marring it against further usage. When the forward, release, stroke of the card carriage has been completed and the ejected card reaches last column position, last column contacts 21 open to break the circuit of solenoid 92 and disk 98 returns to inoperative position.

Briefly, then, when a defective spot of the card is sensed by brushes "15, the release mechanism is operated to cause ejection of the card during which the duplicating circuits are prevented from forming and during which slitter disks 98 and 91 are operative to mar the defective card.

Picker 58, in order to deliver the card to card carriage pusher 48, must pass spot detecting contact plate 18. For this reason, contact plate 18 is carried by pivoted lever 11. Near the end, of its forward stroke, the picker 58 abuts plate 18 and actuates the plate counterclockwise. (Fig. 2). The plate remains in cooperative position with brushes 15 until the rear edge of the card haspassed brushes 18 and is then moved further by continued advance of the picker to the dot and dash position shown in Fig. 5. As lever 11 moved to the latter position, a lug I88 thereon moved into latching coaction with a latch lever I8I rigidly carried by a shaft I82. Lever 11 remains in Lae'latchecl position, out of cooperation with brushes 15, until latch lever I82 is unhooked from lug I88.

Lever I82 is not unlatched from lug I08 until the picker on its return stroke has passed contact plate 18. For this purpose, bracket of the picker mechanism is provided'with a special rod I83 bent transversely at its free end. Near the end of the forward stroke of the picker mechanism, the bent end of rod I83 engages a by-pass pawl I84 see Figs. 1 and 2) carried by an arm I05 secured to one end of shaft I02. As the bent end of rod I03 moves to the left and rides past the pawl I04, the latter is rocked clockwise without imparting movement-to arm I05, shaft I02 and latch IOI. During-the return stroke of the picker mechanism, after picker 50 has passed the contact plate 16, the bent end of rod I03 engages pawl I04 and rocks it counterclockwise. This time the pawl transmits its movement to arm I05, shaft I02 and latch III, thereby causing the latch to unhook lug I of lever TI, permitting spring I0 to return plate I6 to normal position.

In order to prevent brushes I5 from interfering with return movement of picker and in order to prevent formation of spot detecting circuits during return of the picker, brushes I5 are lifted out of engagement with plate I5 until the picker has completed its return stroke. As explained before, contacts 63 (Fig. 6) are closed except when the picker mechanism is in rear, starting, position. Thus, while the picker is moving through its return stroke, contacts 53 are closed. Further, when contact plate 16 and its lever 11 were moved aside by picker 50 as the latter completed its forward stroke. the lower end of the lever cammed against an insulating strip I01 of a spring contact blade I00 and moved the blade towards a blade I09. Between them, blades I08 and I09 carry contacts H0. The contacts IIO are timed to close when the rear edge of the card has passed brushes 15. Now, with contacts 50 and H0 closed, the following circuit is formed (Fig. '7) I Brush raising circuit-From line 32, through switch 00, contacts 50, contacts IIO, brush lifting magnet 05 and to line 24.

Magnet 05, as previously explained, when energized raises brushes I5 to the inoperative position shown in Fig. 5. In their raised position, brushes 15 are out of the path of return movement of picker 50.

When latch IN is released from lever 11 near the beginning of the return stroke of the picker mechanism, lever 11 returns to normal position and contacts IIO open. Magnet 05, however, is held energized through a stick circuit, as follows:

From line 24, through magnet 05, contacts a (closed byenergization of magnet 05), contacts 53, and switch 00, to line 02.

The above stick circuit does not open until the picker mechanism reaches its starting position, at which time contacts 63 are opened to break the stick circuit.

Summary The operator grasps finger grip 52 to move the picker mechanism through its forward stroke. Picker 50 feeds the bottom card T out of supply magazine 40. During the forward stroke of the picker, the card is moved past spot detecting brushes I5. In the-event a conductive spot of the card is sensed by brushes 15, the spot detecting circuit is formed, causing energization of slitter-controlling solenoid 02 and release magnet 30. 'Dllring the forward stroke of the picker, the card carriage is being moved through its return stroke. At the end of the forward stroke of the picker and the coincident end of the return stroke of the card carriage, the card is delivered to the carriage. Now, due to operation of release magnet 30, the escapement mechanism is released and immediately moves through its forward stroke with a continuous motion. The card is thereby ejected from the punchingstation and while being ejected is marred by slitters 96 and now in cooperation because of energization of solenoid 92. Also, during ejection of the card, the pattern card mechanism is ineffective to form punch duplicating circuits because of the opening of contacts 30a in the duplicating circuits. When the card has been ejected so that its last column has passed punches I5, last column contacts 21 open to break the circuits of solenoid 02, release magnet 30, and magnet 90.

During the return stroke of the picker mechanism, the brush raising circuits are formed to energize magnet 05 for raising detecting brushes I5 to permit the picker to pass and to prevent formation of spot detecting circuits. At the end of the return stroke of the picker mechanism, contacts 63 are opened to break the stick circuit of magnet 05. The parts are then in initial position.

While the invention has been disclosed in the preferred form, it is to be understood that such variations, changes, and departures as come within the scope of mechanical skill are within the field of the present invention. therefore, to be limited only as indicated by the following claims.

I claim:

1. In combination; punching means to perforate record cards with selected data, means for detecting a defective card portion on its way to the punching means, means for ejecting the card from the punching means, and means controlled by the detecting means upon detecting a defective card portion for conditioning the ejecting means for card ejecting operation.

2. In combination; punching means to perforate record cards with selected data, means for detecting a defective card on its way to the punching means, means for ejecting the card from the punching means,'means controlled by the detecting means upon detecting a defective card for conditioning the ejectingmeans for operation, and a device also controlled by the detecting means for marking the defective card during its ejection to denote its defectiveness.

3. In a machine in which automatic data duplicating means are provided to record duplicate data on record cards; the combination of means for detecting defective cards on their way to the I duplicating means, means controlled by the detecting means for ejecting defective cards from the duplicating means, and means also controlled by the detecting device for disabling the duplicating means during ejection of the defective cards.

4. In a machine in which automatic data duplicating means are provided to record duplicate data on record cards; the combination of means for detecting defective portions of a card before such portions reach the duplicating means, and

' means controlled by the detecting means upon detecting defective portions of a card for disabling abling the automatic data selecting means.

6. In combination; punching means to perforate cards with selected data, means for detecting It is intended,

a defective card portion on its way to the punchv said operating means to be operated upon, acard supply magazine, mechanism for delivering a card from the magazine to the feeding means, means for detecting a defective card as the latter is being delivered to the feeding means, and means controlled by the detecting means upon detecting a defective card for preventing stepby-step feed of the card by the feeding means.

8. In a machine having means for operating on a card; the combination of feeding means to feed a card step-by-step through the operating means to be operated upon, a card supply magazine, mechanism fordelivering a card from the magazine to the feeding means, means for de-' tectlng a defective card as the latter is being delivered to the feeding means, and means controlled by the detecting means upon detecting a defective card for preventing step-by-step feed of the card by the feeding means and causing continuous movement of the feeding means to eject the defective card delivered thereto.

9. In a. machine of the class described; a card carriage for feeding a card, a card supply magazine, a reciprocatable picker for delivering a card during its forward stroke. from the magazine to the carriage, card sensing means located between the magaz e and the carriage for sensing a card for defective portions as the card is being delivered to the carriage, and means controlled by the sensing means upon sensing a defective card for manifesting the defectiveness of the card.

10. In a machine. of the class described, a card carriage for feeding a card, a card supply magazine, a reciprocatable picker for delivering a card during its'forward stroke from the magazine to the carriage, card sensing means located between the magazine and the carriage for sensing the card for conductive spots and past. which the picker moves to complete its forward stroke, and means for automatically removing the sensing means from the path of the picker during the' return stroke of the picker.

11. In a machine of the class described; a card carriage for feeding a card, a card supply mag azine, means for delivering a card from the magazine to the carriage, card sensing conductive elements between which the card moves as the card is being delivered to the carriage for sensing during which the aforesaid conductive elements may form said circuit and including a contact elementconnected to the picker for movement synchronous with the picker movement.

13. In a machine having means for operating on a card; the combination of means detecting a defective card on its way to aforesaid operating means, means controlled by the detecting means upon detecting a defective card for manifesting defectiveness of the card, and means also controlled by the detecting means for disabling the aforesaid operating means from operating on a defective card.

14. In a machine having punching means to punch-record cards with selected data; the combination of a card carriagefor feeding a card through the punching means, means for delivering a card to the carriage, meansfor detecting a defective portion of the card as the latter is being delivered to the carriage, and means controlled by the detecting means'upon; detecting a defective card portion for manifesting the defectiveness of the card.

15. In a card punchingapparatus; the combination of means for punching a card with coded designations, means for detecting defective portions of a card prior to such portions reaching the punching means, and means controlled by the detecting means upon detecting a defective card for manifesting its defectiveness.

16. A machine for operating on statistical cards having index point positions; comprising punching means to perforate the index positions of the cards, one card at a time, to represent selected information in coded form, in combination with means to detect a defective card, and means controlled by the detecting means to mani fest defectiveness. of the card, said manifesting means including a device for marring the defective card to prevent its subsequent use.

17. A machine for operating on statistical cards having index positions; comprising punching means to perforate the index positions of the cards, one card at a time, to represent selected information. in coded form, in combination with means for detecting defective portions of a card on their way to the punching means,'and means controlled by the detecting means for manifesting defectiveness of the card portions, said manifesting means including a cutting device for cutting the defective card to render it unfit for further use.

18. In-a machine operating on statistical cards; means to record information on said cards, and means for ejecting the cards, in combination with means to detect defective cards running through the machine and means controlled by the detecting means upon detecting a defective card for conditioning the ejecting means to eject such card and simultaneously disabling'the recording means from operating during such,

ejection.

19. In a machine operating on statistical cards having columns of index positions; meansto punch the index positions of the cards selectively to record data. in coded form and means to eject the cards, in combination with means for detecting a defective card in the machine and means controlled by the detecting means for conjointly conditioning the ejecting means to eject the defective card and disabling the punching means from operating during such ejection.

20. In a machine operating on a statistical record sheet having columns of index positions;

punches to punch the columns of the sheet, one column at a time, and sheet feeding means operable to feed the sheet column-by-column past the punches to enable the latter to punch the columns in succession, in combination with means to detect a defective sheet portion and means controlled by the detecting means upon detecting a defective sheet portion for preventing a.

coiumn-by-column feed of the sheet by said feeding means.

21. In a machine operating on a statistical rec- 0rd sheet having columns of index point positions; punches to perforate the index positions of the sheet-with data representations and a set of selectors for selecting the punches to operate in accordance with the data to be represeated on the sheet. in combination with means to detect a defective sheet portion and means controlled by the detecting means upon detecting a defective sheet portion for preventing operation of said set of selectors.

22. In a card punching machine operating on a statistical record sheet having columns of index point positions; punching means to perforate the index point positions of the columns to represent information in coded form in combination with means to detect defective unpunched material of the sheet in the punching machine and means controlled by the detecting means upon detecting defective unpunched sheet material for manifesting defectiveness oi the sheet.

CIMNTEHRET. 

